The invention relates to a method, a device, and a computer program product for operating a motor vehicle in which a radiation source is controlled dependent upon a position sensor.
Motor vehicles are being increasingly equipped with cameras or sensors. These cameras or sensors may be used, for example, for monitoring the health status of the vehicle occupant. Monitoring the health status of the vehicle occupant can contribute to increasing traffic safety.
The object of the invention is to create a method and corresponding device that contributes to the health status of the vehicle occupant being reliably detectable.
This and other objects are achieved by a method for operating a motor vehicle, with which a position sensor is assigned whose measurement signal includes spatial information regarding a predetermined area of a vehicle interior of the motor vehicle. At least one radiation source is associated that emits a predetermined radiation. At least one vital sensor having a detector is associated that detects a portion of the radiation emitted by the radiation source striking it and whose measurement signal is representative of at least one vital parameter of a given vehicle occupant. As a function of the measurement signal of the position sensor, a position of at least one predetermined reference body part of the vehicle occupant in question is determined, and as a function of the detected position of the predetermined reference body part of the vehicle occupant in question, an orientation of the radiation source is controlled.
According to a first aspect of the invention, the invention is characterized by a method and corresponding device for the operation of a motor vehicle. According to this first aspect, a position sensor is assigned to the motor vehicle whose measurement signal captures spatial information regarding a predetermined area of a vehicle interior of the motor vehicle. Moreover, at least one radiation source is assigned to the motor vehicle that emits a predetermined radiation. Additionally, at least one vital sensor having a detector is disposed in the motor vehicle that detects the portion of the radiation emitted by the radiation source striking it. As a function of a raw measurement signal of the detector of the vital sensor, a measurement signal of the vital sensor may be generated. The measurement signal of the vital sensor is representative of at least one vital parameter of a given vehicle occupant. As a function of the measurement signal of the position sensor, a position of at least one predetermined reference body part of the vehicle occupant in question is established. As a function of the established position of the predetermined reference body part of the vehicle occupant in question, an orientation of the radiation source is controlled.
In this manner, the radiation source in the motor vehicle may be controlled in a simple and reliable fashion. Due to the position sensor, the orientation of the radiation source may be adapted to a movement of the vehicle occupant in question or at least to a movement of the predetermined reference body part. Thus, it is possible to guarantee that, even when the vehicle occupant in question moves, a reflected portion of the radiation emitted by the radiation source will strike the vital sensor. Here, the predetermined reference body part of the vehicle occupant in question is used as a reference to establish the direction in which the radiation from the radiation source should be directed in order to allow the determination of the at least one vital parameter. In addition, by virtue of the movement-adapted orientation of the radiation source, it is possible to contribute to the safety of the vehicle occupant in question.
According to one embodiment of the first aspect, the at least one vital parameter of the vehicle occupant in question is detected as a function of the measurement signal of the vital sensor.
In this context, the radiation source is particularly directed at an area of skin of the vehicle occupant in question, for example, at his or her neck or in the facial area. The portion of the predetermined radiation reflected on the area of skin can provide information regarding one or more vital parameters of the vehicle occupant in question such that, in this manner, one or more vital parameters may be ascertained in a contact-free fashion without limiting the movement of the vehicle occupant in question. In this manner, it is not necessary for sensors to be directly attached to the vehicle occupant in question, which is perceived as uncomfortable by said occupant. Moreover, the clothing of the vehicle occupant in question has no influence because, as a rule, at least the facial area of the vehicle occupant in question is not covered by clothing.
According to an additional embodiment of the first aspect, the at least one vital parameter of the vehicle occupant in question is detected as a function of the measurement signal of the vital sensor on the basis of vibrocardiography.
Vibrocardiography is a method in which radiation from a radiation source, for example, laser light, is directed onto a surface of an object to be examined and a reflected portion of the laser light is analyzed. Based on the surface structure of the object, the laser light is reflected in such a way that an interference structure may be observed at a corresponding distance from the object that contains information regarding the composition of the surface and the movement of the object. In this context, vibrocardiography may be used for the detection of vital parameters in that the radiation from the radiation source is directed onto an area of skin of the occupant in question and the reflected portion of this radiation is detected by means of the vital sensor and the measurement signal of the vital sensor is subsequently processed. For example, a laser used as a radiation source may be directed onto the region of the carotid artery of the vehicle occupant in question, such that, due to the pulsing carotid artery, a periodic movement of the reflected interference structure may be observed. Thus, for example, a pulse or even a pulse type of the vehicle occupant in question may be detected.
According to another embodiment of the first aspect, the at least one vital parameter of the vehicle occupant in question is determined as a function of the measurement signal of the vital sensor on the basis of photo oximetry. In this context, photo oximetry describes a method in which radiation from a radiation source, for example, laser light, is directed onto an object to be investigated and the reflected and/or transmitted portion of the laser light is analyzed. For example, laser light reflected against an area of skin of the vehicle occupant in question may be analyzed with regard to its intensity. In this manner, for example, blood oxygen content and/or blood sugar levels may be ascertained as a vital parameter of the vehicle occupant in question in a contact-free manner. Blood oxygen content as well as blood sugar levels of the vehicle occupant in question have an effect on the coloration of the blood, for which reason, for example, oxygen-richer blood appears brighter than low-oxygen blood. The different coloration of the blood within the area of skin of the vehicle occupant in question leads to a different intensity of the reflected laser light such that, in this manner, the required vital parameters may be ascertained by the analysis of the reflected laser light.
According to an additional embodiment of the first aspect, as a function of the detected position of the reference body part of the vehicle occupant in question and the measurement signal of the vital sensor, the radiation source is controlled in the sense of its orientation toward at least one prespecified preferred position of the vehicle occupant in question.
In this manner, a high degree of correlation of the measurement signal of the vital sensor to the respective vital parameter becomes possible. A preferred position in this context may be a carotid artery or a temple of the vehicle occupant in question.
Another option lies in activating more than one predetermined preferred position of the vehicle occupant in question as a function of the measurement signal of the vital sensor. For example, in the case of one vehicle occupant, a good correlation of the measurement signal of the vital sensor to the respective vital parameter may be obtained by orienting the radiation source toward the carotid artery and, in the case of another vehicle occupant, by orienting the radiation source toward the region of the temple.
Moreover, one of the preferred positions, such as an area of skin on the neck of the vehicle occupant in question, may be covered by a piece of clothing, for example, a scarf. For this reason, another preferred position, such as the region of the temple, may be suitable for ascertaining the at least one vital parameter of the vehicle occupant in question.
The preferred position in which, for a given vehicle occupant, the highest correlation is present between the measurement signal of the vital sensor and the respective vital parameter to be ascertained may be designated as the optimal preferred position on that specific vehicle occupant.
Alternatively or additionally, it may be advantageous for the orientation of the radiation source to be optimized with respect to the greatest possible correlation between the measurement signal of the vital sensor and the respective vital parameter to be ascertained. In this context, the radiation from the radiation source is initially oriented toward a prespecified preferred position on the vehicle occupant in question and the radiation from the radiation source is varied in the sense of an orientation in a prespecified area around the prespecified preferred position. By evaluating where the respective measurement signal of the vital sensor has the greatest correlation to the respective vital parameter, an adapted preferred position may be ascertained accordingly.
According to an additional embodiment of the first aspect, a radiation intensity of the radiation source is controlled as a function of the measurement signal of the vital sensor.
In this manner, it becomes possible for an intensity of the reflected portion of the radiation to reach a prespecified second threshold value, thus allowing the reception of a measurement signal of the vital sensor. For example, a prespecified signal-to-noise ratio may be attained in this manner such that the detection of at least one vital parameter of the vehicle occupant in question becomes possible.
According to an additional embodiment of the first aspect, the radiation source is activated or deactivated as a function of the measurement signal of the position sensor. In this manner, the safety of the vehicle occupant in question is ensured, inter alia, in that the radiation source is not activated until the position of the vehicle occupant in question and/or of the respective predetermined reference body part has been ascertained.
In addition, this embodiment includes the contact-free measurement of the at least one vital parameter of the vehicle occupant in question, for example, by use of a plurality of radiation sources disposed in the motor vehicle. Thus, for example, one radiation source may be positioned in a headrest of the vehicle occupant in question and oriented toward an area of skin on the neck of the vehicle occupant in question. Another radiation source may be disposed in the instrument panel of the motor vehicle and be directed toward an area of skin in the region of one of the temples of the vehicle occupant in question.
Moreover, by the activation or deactivation of the radiation source, the measurement and detection of the at least one vital parameter of the vehicle occupant in question may occur within a certain time interval and need not be conducted continuously for the duration of the driving cycle.
According to another embodiment of the first aspect, a characteristic value is determined for a movement dynamic as a function of the measurement signal of the position sensor. Moreover, as a function of the characteristic value for the movement dynamic, the radiation source is activated or deactivated.
For example, depending on the situation, a rapid movement of the vehicle occupant in question may occur that the radiation source may not necessarily be able to follow with regard to its orientation. If, in this context, a characteristic value is determined for the movement dynamics that exceeds a predetermined third threshold value, the radiation source may be deactivated. In this manner, the safety of the vehicle occupant in question is guaranteed even in the case of sudden movements.
According to another embodiment of the first aspect, the position sensor comprises a camera. In this context, the camera may be embodied as an individual camera or as a stereo camera and thus provide spatial information for a predetermined area of the vehicle interior of the motor vehicle. Cameras are already frequently disposed in motor vehicles for other purposes such that, for example, a pre-existing resource may be used in this situation.
According to another embodiment of the first aspect, the position sensor comprises an ultrasonic sensor. This is another option for capturing spatial information in a predetermined area of the vehicle interior of the motor vehicle.
According to another embodiment of the first aspect, the radiation source comprises a laser. Due to its radiation properties, the laser represents a preferred radiation source that emits coherent light with a high degree of brilliance. For this reason, laser light may be directed in a controlled fashion at an area of skin of the vehicle occupant in question. By analyzing the portion of the laser radiation reflected on the area of skin, a vital parameter of the vehicle occupant in question may be determined using, for example, vibrocardiography or photo oximetry.
According to another embodiment of the first aspect, a person sensor is assigned to the motor vehicle whose measurement signal is representative of a personal identifying characteristic of the vehicle occupant in question. An identification is conducted as a function of the measurement signal of the person sensor, thus providing an identified vehicle occupant.
In this manner, the measurement of the vital parameter or parameters may be associated with the identified vehicle occupant, thus allowing, for example, a person-specific measurement of the at least one vital parameter.
Moreover, the identification of the vehicle occupant in question allows one or more predetermined preferred positions to be associated with the identified vehicle occupant in question. Thus, for example, a data memory may be used to store which preferred position of the identified vehicle occupant in question was found to be the optimal preferred position for determining the vital parameter or parameters during the previous driving cycle such that, in a subsequent driving cycle, the optimal preferred position for the identified vehicle occupant in question may be activated by the radiation source.
Moreover, the respectively adapted preferred position may be stored in relation to the identified vehicle occupant in question. Thus, when the vehicle occupant in question is identified again during a subsequent driving cycle, information is available regarding the optimal preferred position of the identified vehicle occupant and regarding a person-specific optimized orientation of the radiation source in the region of the optimal preferred position.
According to another embodiment of the first aspect, the position sensor is additionally used as a person sensor. In this manner, a pre-existing sensor is used for an additional purpose and additional sensors are not necessarily required.
According to another embodiment of the first aspect, a respective trend of the measurement signal of the vital sensor is associated with the identified vehicle occupant in question. Thus, it is possible for the measurement signal of the vital sensor to be directly associated with an identified vehicle occupant without any additional analysis. Further analysis of the measurement signal may occur, for example, outside of the motor vehicle and/or at a later time.
According to a second aspect, one system comprises the device for operating a motor vehicle, the position sensor, the radiation source, and the vital sensor with the detector.
According to a third aspect, the invention is characterized by a computer program product comprising executable program code, with the program code performing the method for operating a motor vehicle according to the first aspect upon its execution by a data processing unit.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.